turn off jemalloc debug mode for mysql builds, it's more than we need

cmake_modules/TokuThirdParty.cmake

@@ -6,7 +6,8 @@ if (NOT EXISTS "${JEMALLOC_SOURCE_DIR}/configure")
   message(FATAL_ERROR "Can't find jemalloc sources.  Please check them out to ${JEMALLOC_SOURCE_DIR} or modify JEMALLOC_SOURCE_DIR.")
 endif ()
 set(jemalloc_configure_opts "CC=${CMAKE_C_COMPILER}" "--with-jemalloc-prefix=" "--with-private-namespace=tokudb_jemalloc_internal_" "--enable-cc-silence")
-if (NOT CMAKE_BUILD_TYPE MATCHES Release)
+option(JEMALLOC_DEBUG "Build jemalloc with --enable-debug." OFF)
+if (JEMALLOC_DEBUG)
   list(APPEND jemalloc_configure_opts --enable-debug)
 endif ()
 ExternalProject_Add(build_jemalloc